//
// aegis - project change supervisor
// Copyright (C) 1999, 2002-2006, 2008, 2011, 2012 Peter Miller
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//

#include <libaegis/output/filter/base64.h>

static char base64[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static inline int
map64(int n)
{
    return base64[n & 0x3F];
}


output_filter_base64::~output_filter_base64()
{
    //
    // Make sure all buffered data has been passed to our write_inner
    // method.
    //
    flush();

    switch (residual_bits)
    {
    case 4:
        deeper_fputc(map64(residual_value << 2));
        deeper_fputc('=');
        output_column += 2;
        break;

    case 2:
        deeper_fputc(map64(residual_value << 4));
        deeper_fputc('=');
        deeper_fputc('=');
        output_column += 3;
        break;
    }
    if (output_column)
        deeper_fputc('\n');
}


output_filter_base64::output_filter_base64(const output::pointer &a_deeper) :
    output_filter(a_deeper),
    residual_value(0),
    residual_bits(0),
    output_column(0),
    pos(0),
    bol(true)
{
}


output::pointer
output_filter_base64::create(const output::pointer &a_deeper)
{
    return pointer(new output_filter_base64(a_deeper));
}


void
output_filter_base64::write_inner(const void *p, size_t len)
{
    const unsigned char *data = (const unsigned char *)p;
    while (len > 0)
    {
        unsigned char c = *data++;
        --len;

        residual_value = (residual_value << 8) | c;
        residual_bits += 8;
        for (;;)
        {
            residual_bits -= 6;
            deeper_fputc(map64(residual_value >> residual_bits));
            ++output_column;
            if (residual_bits == 0 && output_column > 70)
            {
                deeper_fputc('\n');
                output_column = 0;
            }
            if (residual_bits < 6)
                break;
        }
        ++pos;
        bol = (c == '\n');
    }
}


long
output_filter_base64::ftell_inner(void)
    const
{
    return pos;
}


void
output_filter_base64::end_of_line_inner(void)
{
    if (!bol)
        write_inner("\n", 1);
}


nstring
output_filter_base64::type_name(void)
    const
{
    return ("base64 " + output_filter::type_name());
}


// vim: set ts=8 sw=4 et :